The present invention relates to an eye characteristic measuring apparatus, and particularly to an eye characteristic measuring apparatus for measuring an optical characteristic of a subject eye precisely and at high speed with plural sensitivities by using a wavefront sensor.
As a conventional corneal shape measuring apparatus, there is known an apparatus which projects an index, obtains an imaging position of the index, and measures a corneal shape. Besides, as an apparatus for measuring an optical characteristic of an eye, whose patent application was filed by the present assignee, there exists an apparatus in which pint adjustment of an illuminating optical system is performed through a received light level of a light receiving part, and pint adjustment of a light receiving optical system is performed on the basis of an optical characteristic (S) obtained from the output of the light receiving part, or an apparatus which receives converted beams from a conversion member, the number of which is smaller than that at the measurement, and performs an adjustment (Japanese Patent Application No. 9-137630 and No. 2000-321509).
Besides, there is proposed an eye characteristic measuring apparatus which measures wavefront aberrations of a subject eye more efficiently and suitably and displays them irrespective of the state of the subject eye (Japanese Patent Application No. 2001-388965 and No. 2001-376717). In this apparatus, a first illuminating optical system illuminates a minute area on a retina of a subject eye with a first light flux from a first light source part. A first light receiving optical system guides a part of a light flux reflected and returned from the retina of the subject eye through a first conversion member (Hartmann plate). Peak extraction of spot images is carried out on the basis of a first signal from the first light receiving part, and a column number of a lattice point is decided from the vicinity of the central axis in the horizontal direction on the basis of the extracted peak of the spot image, and then, a row number is decided on the basis of the spot image position of the decided column number, so that lattice point coordinates are decided. An arithmetic part carries out an operation on the optical characteristic of the subject eye on the basis of the lattice point coordinates of the respective spots.
However, in an apparatus for measuring an optical characteristic of a subject eye having aberrations, in a case where an aberration amount is large, a variation amount of a spot image becomes large, and an accurate measurement has been sometimes difficult.